oil pump pickup height
 

Guys,

In the process of putting the oil-pan on a 289"/347".

It there an optimum height for the end of the oil-pickup from the bottom of the pan ?

Checking the pickup height with clay, the cork side rail gaskets laying in place but not compressed, it can range from about 0.20" to 0.40".

Was going to split the difference and try to get 0.25-0.30, but thought I would see what some of the engine builders prefer.

FWIW the pan is an AVIAD 8qt. The engine is a hydraulic roller that should top out at 6000 or so.

Would really like to get this thing buttoned up today.

Thanks, Pete

Shoot for .375" or slightly greater.

3/8"
 

Chas,

Apparently your in good company suggesting pickup clearance at "3/8's"...finally dug out a reference in one of Smokey Yunick's books. His comment was "no closer than 3/8's".

Oil related problems are a touchy subject for me...inconsistent oil pressure cost me the last engine...

Thanks, Pete

Understood Pete. Getting too close to the pan floor can cause a little cavitation. Sorta sucking the pump 'dry'. You want a nice 'cushion' of url under there. :)

between 1/4" and 3/8" clearance
 

Peter Munroe. Pete you have the clearance between the bottom of the pan and the screen. Get the largest pickup tube for the motor and oil pan. Also add 1 extra quart of oil to the motor to make sure you always have oil around the pickup. Unless the oilpan has no baffles or trap doors you will need to watch this too. Have seen motors lost with trap doors not letting in oil to the sump area. This happens on road courses no street driving unless you get "G" carving. Last note, add an accusump to the car for starting the motor and controlling oil pressures if you should get the high "G" turning feel. This setup has saved many a motor, mine twice. 2 quart is good, 3 is better. Rick L.

Pete,
Fill that sump with water and check for leaks at the welds prior to assembly. Ask me how I know:(.
Wolfgang

thanks I'll check that
 

All,

Think I will try your idea of adding water to oil pan...check for leaks and also take a look at where 6-7-8-9-10 quarts sits in the pan...it is a new pan anyway.

At oil changes always checked the oil level after adding 7qts...8qts...9 to the pan...THEN starting the engine and checking to see how much I need to add after the filter and any passage way drain back has taken place. Never hurts to do it again...

The old pan was the original Cobra type AVIAD with the trap door assembly mounted symmetrically front/rear side/to side. This pan is the newer version of the Cobra AVIAD pan. The new pan's trap door assembly is mounted on the diagonal. Canton offers a similar pan.

Got pickup as high as it will go without elongating bolts holes and it is now at 3/8ths plus...a little...will try clay again before I button it up...but this seems pretty good...(it does take the gasket into account).

Thanks, Pete

Running yet Pete?

Rick, and all.

Oil pickup is now set about 0.40"...(kept getting bad measurements using some sort of putty that was too sticky and elastic to be measurable...found REAL modeling clay at a craft store..made it easy to get repeatable measurements).

Made up a stable TDC fixture that bolts to the block. Used a dial indicator to find TDC consistently...timing pointer is now set pretty close to TDC.

Oil pan is on...used a Jegs rubber pan gasket with grommets.
Let is settle as the end gaskets were slow to pull down...will go around one more time later and add blue locktite when I finally pull up all the bolts tight to the metal grommets.

Today, cleaned up an old head gasket, dug out the head studs, and temporarily set a head on to prepare for claying the valve clearance.

Took two of the old roller lifters apart to remove the springs and set them up as solids for claying the pistons and verifying the valve clearance with the new cam...doubt there will be any problem, but fun (SORT OF!!) to check...set the new cam 2 degrees retarded compared to the old one...ie: straight up...Comp grinds it 4 advanced built in...(I am guessing to accommodate heavy cars)...the Cobra is light and seemed good to shift the power up the rpm band, if only a little. Torque down low has never been a problem.
.
With the cam in a comparatively retarded setting who knows where the clearances will end up. New cam lift is minorly less lift and more duration...Again mainly an exercise to do it. Doubt there is anything close.

Need to verify the geometry on the new roller rockers...the ratio is the same but don't want the rocker touching the stud...not quite sure how to do that other than with machinist blue...which I don't have...something will work...

Actually at this point things are finally coming together...

Pete

Pete,

Your "fixture" for finding true TDC was the positive stop method?

A paperclip works to check clearance between the rocker stud and rocker arm with valve closed and valve open at full lift.
There are many other clearances to check in the valvetrain: rocker arm to pushrod, pushrod to cyl head, rockerarm to retainer, retainer to valve stem seal, spring coil bind at full lift, valve to piston clearance etc.

These days, cams are ground with advance to allow the "lazy engine builder" to fit the cam "dot to dot". The built-in advance allows for timing chain stretch throughout the life of the engine.

TDC tool
 

http://www.clubcobra.com/photopost/d...N6304_comp.JPG Gary,

Made this fixture from a aluminum tube...then I saw David Gagnard's idea...he used an open slot which is easier than trying to get the two bolts into the block centered.

The 5/16" pointer bolt is too big, and the #18 pitch thread too coarse. Fit is pretty sloppy. Would try a fine machine screw if I did it again...hard to use to repeat TDC.

The bar did work well to support the dial indicator solidly. My magnetic base was always creeping.

Using the dial indicator had a problem with the new rings causing a chatter as you rotated the crank...hit the bores with WD-40 and that smoothed out and made finding TDC repeatable.

The PAPER CLIP gauge is great idea for checking the rocker arm clearance, I will give that a try.

Thanks, Pete



http://www.clubcobra.com/photopost/d...N6294_comp.JPG